On 19/07/2016 10:57, Marc Zyngier wrote:
> The kprobe enablement work has uncovered that changes made by
> a guest to MDSCR_EL1 were propagated to the host when VHE was
> enabled, leading to unexpected exception being delivered.
>
> Moving this register to the list of registers that are always
> context-switched fixes the issue.
>
> Reported-by: Tirumalesh Chalamarla <Tirumalesh.Chalamarla@xxxxxxxxxx>
> Tested-by: Tirumalesh Chalamarla <Tirumalesh.Chalamarla@xxxxxxxxxx>
> Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
> ---
> arch/arm64/kvm/hyp/sysreg-sr.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/arch/arm64/kvm/hyp/sysreg-sr.c b/arch/arm64/kvm/hyp/sysreg-sr.c
> index 0f7c40e..a327e35 100644
> --- a/arch/arm64/kvm/hyp/sysreg-sr.c
> +++ b/arch/arm64/kvm/hyp/sysreg-sr.c
> @@ -27,8 +27,8 @@ static void __hyp_text __sysreg_do_nothing(struct kvm_cpu_context *ctxt) { }
> /*
> * Non-VHE: Both host and guest must save everything.
> *
> - * VHE: Host must save tpidr*_el[01], actlr_el1, sp0, pc, pstate, and
> - * guest must save everything.
> + * VHE: Host must save tpidr*_el[01], actlr_el1, mdscr_el1, sp0, pc,
> + * pstate, and guest must save everything.
> */
>
> static void __hyp_text __sysreg_save_common_state(struct kvm_cpu_context *ctxt)
> @@ -37,6 +37,7 @@ static void __hyp_text __sysreg_save_common_state(struct kvm_cpu_context *ctxt)
> ctxt->sys_regs[TPIDR_EL0] = read_sysreg(tpidr_el0);
> ctxt->sys_regs[TPIDRRO_EL0] = read_sysreg(tpidrro_el0);
> ctxt->sys_regs[TPIDR_EL1] = read_sysreg(tpidr_el1);
> + ctxt->sys_regs[MDSCR_EL1] = read_sysreg(mdscr_el1);
> ctxt->gp_regs.regs.sp = read_sysreg(sp_el0);
> ctxt->gp_regs.regs.pc = read_sysreg_el2(elr);
> ctxt->gp_regs.regs.pstate = read_sysreg_el2(spsr);
> @@ -61,7 +62,6 @@ static void __hyp_text __sysreg_save_state(struct kvm_cpu_context *ctxt)
> ctxt->sys_regs[AMAIR_EL1] = read_sysreg_el1(amair);
> ctxt->sys_regs[CNTKCTL_EL1] = read_sysreg_el1(cntkctl);
> ctxt->sys_regs[PAR_EL1] = read_sysreg(par_el1);
> - ctxt->sys_regs[MDSCR_EL1] = read_sysreg(mdscr_el1);
>
> ctxt->gp_regs.sp_el1 = read_sysreg(sp_el1);
> ctxt->gp_regs.elr_el1 = read_sysreg_el1(elr);
> @@ -90,6 +90,7 @@ static void __hyp_text __sysreg_restore_common_state(struct kvm_cpu_context *ctx
> write_sysreg(ctxt->sys_regs[TPIDR_EL0], tpidr_el0);
> write_sysreg(ctxt->sys_regs[TPIDRRO_EL0], tpidrro_el0);
> write_sysreg(ctxt->sys_regs[TPIDR_EL1], tpidr_el1);
> + write_sysreg(ctxt->sys_regs[MDSCR_EL1], mdscr_el1);
> write_sysreg(ctxt->gp_regs.regs.sp, sp_el0);
> write_sysreg_el2(ctxt->gp_regs.regs.pc, elr);
> write_sysreg_el2(ctxt->gp_regs.regs.pstate, spsr);
> @@ -114,7 +115,6 @@ static void __hyp_text __sysreg_restore_state(struct kvm_cpu_context *ctxt)
> write_sysreg_el1(ctxt->sys_regs[AMAIR_EL1], amair);
> write_sysreg_el1(ctxt->sys_regs[CNTKCTL_EL1], cntkctl);
> write_sysreg(ctxt->sys_regs[PAR_EL1], par_el1);
> - write_sysreg(ctxt->sys_regs[MDSCR_EL1], mdscr_el1);
>
> write_sysreg(ctxt->gp_regs.sp_el1, sp_el1);
> write_sysreg_el1(ctxt->gp_regs.elr_el1, elr);
>
Can you add Fixes and Cc: stable headers? Thanks,
Paolo
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